The Territory of Louisiana was established on July 4, 1805. Admitted as the 18th state, Louisiana achieved statehood on April 30, 1812. (Brit; Wiki)
See also: https://www.britannica.com/place/Louisiana-state
The graph displays the other subjects mentioned on the same pages as the subject "Louisiana". If the same subject occurs on a page with "Louisiana" more than once, it appears closer to "Louisiana" on the graph, and is colored in a darker shade. The closer a subject is to the center, the more "related" the subjects are.